The invention relates to an apparatus for teaching a gripping device. The gripping device is used for loading and unloading a clamping device, for example a chuck, of a machine tool and/or a pallet. For example, the gripping device may be used to remove blanks from one or more pallets and insert them into the chuck of a machine tool. The gripping device is also used to remove machined workpieces from the chuck and deposit them on a pallet. The gripping device must be taught in order to know the exact position of the blanks on the pallet or know the exact position of the chuck. Otherwise, blanks that have not been machined or workpieces that have been machined will not be grasped in a precise manner.
For example, it has been known from publication DE 60 2004 013 107 T2 to accomplish teaching by touching three or more reference points on the workpiece or on a holding device. A tool tip of the robot is brought in exact alignment with reference points of the workpiece or the holding device, and the three-dimensional positions of each reference point are measured. Known motion sequences of robots can then be applied to newly trained or learned positions. Such mechanical touching is very expensive.
In order to minimize the expense during the teaching phase and to increase the teaching accuracy of the device publication DE 60 2004 013 107 T2 further suggests that image sensors be used and that the three-dimensional position be computed based on the image detected by the image sensor. To accomplish this, for example, CCD cameras can be used.